Question: The top story in USA Today on December 2, 1993, reported that "two research teams, one at Harvard and one in Germany, found that the risk of a heart attack during heavy physical exertion . . . was two to six times greater than during less strenuous activity or inactivity" (Snider, 2 December 1993, p. 1A). It was implicit, but not stated, that these results were for those who do not exercise regularly.

a. There is a confidence interval reported in this statement. Explain what it is and what characteristic of the population it is measuring.

b. The report also stated that "frequent exercisers had slight or no increased risk." (In other words, frequent exercisers had slight or no increased risk of heart attack when they took on a strenuous activity compared with when they didn't.) Do you think that means the relative risk was actually 1.0? If not, discuss what the statement really does mean in the context of what you have learned in this chapter.